Polypropylene Composition Radiation Stability Aliphatic Alcohol Stabilizer
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Solution Overview
Problem
Gamma and e-beam radiation sterilization methods deteriorate the impact properties of polypropylene articles due to degradation, necessitating the development of polypropylene compositions with enhanced radiation stability.
Innovation Solution
A polypropylene composition comprising a propylene polymer and an aliphatic alcohol with at least two hydroxyl groups, such as straight chain C5-C20 diols, C4-C30 cyclic alcohols, polycarbohydrates, and branched acyclic diols, which maintains mechanical and optical properties even after radiation exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radiation sterilization is used to sterilize polypropylene articles, then sterilization effectiveness is improved, but impact properties deteriorate
Solution Approach 1:
The patent applies preliminary action by incorporating radiation stabilizers into the polypropylene composition before radiation sterilization. The stabilizers (such as hindered amine stabilizers, hydroxylamine, nitrone stabilizers, and organic phosphites) are pre-added to the polymer matrix to prevent degradation before the radiation exposure occurs, thereby maintaining impact properties while allowing effective sterilization.
Solution Approach 2:
The patent uses radiation stabilizers as intermediary substances that mediate between the radiation sterilization process and the polypropylene material. These stabilizers absorb or scavenge the harmful radiation effects, protecting the polypropylene matrix from direct degradation while allowing the sterilization process to proceed effectively.
2Stability of the object's composition
If conventional stabilizing systems are used in polypropylene, then radiation stability is improved, but composition complexity increases
Solution Approach 1:
The patent merges multiple stabilizing functions into a single integrated composition system. By combining hindered amine stabilizers, hydroxylamine, nitrone stabilizers, and organic phosphites in specific proportions within the polypropylene matrix, the invention creates a synergistic stabilizing system that provides comprehensive radiation protection while maintaining manageable composition complexity.
Solution Approach 2:
The patent applies parameter changes by optimizing the concentration ranges of different stabilizers within the polypropylene composition. By controlling the amount of each stabilizer component (e.g., hindered amine stabilizers at 0.01-5 wt%, hydroxylamine at 0.01-2 wt%, etc.), the invention achieves optimal radiation stability while preventing excessive complexity in the formulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition retains a significant proportion of its impact property, with Charpy Impact Strength remaining at least 50% or more after gamma radiation, effectively minimizing the deterioration caused by radiation sterilization.
Implementation Method 1
an aliphatic alcohol having at least two hydroxyl groups, wherein the aliphatic alcohol is selected from the group consisting of (i) straight chain C5-C20 aliphatic diols, (ii) C4-C30 aliphatic cyclic alcohols, (iii) polycarbohydrates, and (iv) branched acyclic diols having at least one hydroxyl group attached to a tertiary carbon atom
Implementation Method 2
the polypropylene composition has reduced deterioration of its impact property, even after being subjected to irradiation with gamma or e-beam radiation
Data Source
AI summary
The invention relates to a polypropylene composition having improved radiation stability, comprising: a) a propylene polymer present in amount ≥94.0 wt. %; and b) aliphatic alcohol having at least two hydroxyl groups, wherein the aliphatic alcohol may be selected from the group consisting of (i) straight chain C5-C20 aliphatic diols, (ii) C4-C30 aliphatic cyclic alcohols, (iii) polycarbohydrates. and (iv) branched acyclic diols having at least one hydroxyl group attached to a tertiary carbon atom, and combinations thereof, and c) optionally, one or more further additives. The invention further relates to radiation sterilized articles comprising such polypropylene composition and the use of such polypropylene composition for improving radiation stability of articles that are subjected to radiation.